This invention relates to a plug device used to seal the interior of a pipeline, and more particularly to an inflatable, expansible, multisize plug device for sealing the interior of a pipeline or other conduit and for locking engagement therewith. The device is particularly useful for the portable, releasable and reusable sealing of high pressure pipelines of various sizes.
In the past, various devices have been used and proposed to seal pipeline sections having varying pressures and contents. However, these devices are generally complex, difficult to use, and are inefficient and expensive to manufacture. Specifically, some such plugs have inflatable seals of a looped or continuous nature and, therefore, require adhesive bonding or elaborate sealing structures. Still others are unusable in certain corrosive or high pressure pipeline environments. Finally, some such prior art plug structures are suitable for use only in a specific size or type of pipeline or conduit.
Despite the need for a high pressure, multisize plug device in the art which is efficient to manufacture and use, and which overcomes the limitations and problems of the prior art, none insofar as is known has been proposed or developed.
Accordingly, it is an object of the present invention to provide a plug device of an efficient and reliable design which is usable over a range of sealing diameters to seal conduit of varying diameters and types, and which is usable in a variety of pipeline environments including corrosive and high pressure environments.